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How to generate a n-digit number using JavaScript?

Last Updated : 12 Jul, 2025
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The task is to generate an n-Digit random number with the help of JavaScript.

You can also generate random numbers in the given range using JavaScript.

Below are the approaches to generate a n-digit number using JavaScript:

Table of Content

Using Math.random()

Get the minimum and maximum number of n digits in variable min and max respectively. Then generate a random number using Math.random()(value lies between 0 and 1). Multiply the number by (max-min+1), get its floor value, and then add a min value to it.

Example: The example below shows how to generate a n-digit number using JavaScript.

HTML 
<!DOCTYPE HTML>
<html>

<head>
    <title>
        Generate a n-digit 
          number using JavaScript
    </title>
    <style>
        body {
            text-align: center;
        }

        h1 {
            color: green;
        }

        #geeks {
            color: green;
            font-size: 29px;
            font-weight: bold;
        }
    </style>
</head>

<body>
    <p>

        <!-- min and max are 5 digit so-->
        Click on the button to 
          generate random 5 digit 
          number
    </p>
    <button onclick="gfg();">
        click here
    </button>
    <p id="geeks">
    </p>
    <script>
        let up = document.getElementById('GFG_UP');
        let down = document.getElementById('geeks');

        function gfg() {
            let minm = 10000;
            let maxm = 99999;
            down.innerHTML = Math.floor(Math
                .random() * (maxm - minm + 1)) + minm;
        } 
    </script>
</body>

</html>

Output:

imp2i1
Output

Math.random() Method and .substring() Method

Math.random() method use .substring() method to generate a random number between 0 and 1. Now we will use to get a part of the random number after converting it to string.

Example: The example shows How to generate a n-digit number using Math.random() Method and .substring() Method.

HTML 
<!DOCTYPE HTML>
<html>

<head>
    <title>
        Generate a n-digit number using JavaScript
    </title>
    <style>
        body {
            text-align: center;
        }

        h1 {
            color: green;
        }

        #geeks {
            color: green;
            font-size: 29px;
            font-weight: bold;
        }
    </style>
</head>

<body style="text-align:center;">
    <p>
        Click on the button to generate
          random 6 digit number
    </p>
    <button onclick="gfg();">
        click here
    </button>
    <p id="geeks">
    </p>
    <script>
        let down = document.getElementById('geeks');

        function gfg() {
            down.innerHTML = ("" + Math.random()).substring(2, 8);
        } 
    </script>
</body>

</html>

Output:

imp2i2
Output

P

PranchalKatiyar
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